Probes for INS

Although blood-brain barrier (BBB) compromise is central to the etiology of diverse central nervous system (CNS) disorders, endothelial receptor proteins that control BBB function are poorly defined. The endothelial G-protein-coupled receptor (GPCR) Gpr124 has been reported to be required for normal forebrain angiogenesis and BBB function in mouse embryos, but the role of this receptor in adult animals is unknown. Here Gpr124 conditional knockout (CKO) in the endothelia of adult mice did not affect homeostatic BBB integrity, but resulted in BBB disruption and microvascular hemorrhage in mouse models of both ischemic stroke and glioblastoma, accompanied by reduced cerebrovascular canonical Wnt-β-catenin signaling. Constitutive activation of Wnt-β-catenin signaling fully corrected the BBB disruption and hemorrhage defects of Gpr124-CKO mice, with rescue of the endothelial gene tight junction, pericyte coverage and extracellular-matrix deficits. We thus identify Gpr124 as an endothelial GPCR specifically required for endothelial Wnt signaling and BBB integrity under pathological conditions in adult mice. This finding implicates Gpr124 as a potential therapeutic target for human CNS disorders characterized by BBB disruption.

Relapse to drug use is often cited as the major obstacle in overcoming a drug addiction. While relapse can occurs for a myriad of reasons it is well established the complex neuroadaptations, which occur over the course of addiction, are major factors. Cocaine, as a potent dopamine transporter blocker, specifically induces alterations in the dopaminergic as well as other monoaminergic neurotransmissions, which lead to cocaine abuse and dependence. Evidence also suggests that adaptations in the endogenous opioids play important roles in pathophysiology of cocaine addiction. Following this evidence, we investigated a combination medication, levo-tetrahydropalmatine (l-THP) and low dose naltrexone (LDN), targeting primarily dopaminergic and endogenous opioid systems as a cocaine relapse prevention treatment. In the present study Wistar rats were used to assess the effects of l-THP and LDN on cocaine self-administration, drug-seeking behavior during cocaine reinstatement, spontaneous locomotion, and effects on the endogenous opioid system. We determine the combination of l-THP and LDN reduces drug-seeking behavior during reinstatement potently than l-THP alone. Additionally, the combination of l-THP and LDN attenuates the sedative locomotor effect induced by l-THP. Furthermore, we revealed that treatment with the combination of l-THP and LDN has an upregulatory effect on both plasma β-endorphin and hypothalamic POMC that was not observed in l-THP-treated groups. These results suggest that the combination of l-THP and LDN has great potential as an effective and well-tolerated medication for cocaine relapse prevention.

Inflammatory disorders of the CNS are frequently accompanied by synaptic loss, which is thought to involve phagocytic microglia and complement components. However, the mechanisms accounting for aberrant synaptic connectivity in the context of CD8+ T cell-driven neuronal damage are poorly understood. Here, we profiled the neuronal translatome in a murine model of encephalitis caused by CD8+ T cells targeting antigenic neurons. Neuronal STAT1 signaling and downstream CCL2 expression were essential for apposition of phagocytes, ensuing synaptic loss and neurological disease. Analogous observations were made in the brains of Rasmussen’s encephalitis patients. In this devastating CD8+T cell-driven autoimmune disease, neuronal STAT1 phosphorylation and CCL2 expression co-clustered with infiltrating CD8+ T cells as well as phagocytes. Taken together, our findings uncover an active role of neurons in coordinating phagocyte-mediated synaptic loss and highlight neuronal STAT1 and CCL2 as critical steps in this process that are amenable to pharmacological interventions.

In the arcuate nucleus of the hypothalamus (ARH) satiety signaling (anorexigenic) pro-opiomelanocortin (POMC)-expressing and hunger signaling (orexigenic) agouti-related peptide (AgRP)-expressing neurons are key components of the neuronal circuits that control food intake and energy homeostasis. Here, we assessed whether the catecholamine noradrenalin directly modulates the activity of these neurons in mice. Perforated patch clamp recordings showed that noradrenalin changes the activity of these functionally antagonistic neurons in opposite ways, increasing the activity of the orexigenic NPY/AgRP neurons and decreasing the activity of the anorexigenic POMC neurons. Cell type-specific transcriptomics and pharmacological experiments revealed that the opposing effect on these neurons is mediated by the activation of excitatory α1A - and β- adrenergic receptors in NPY/AgRP neurons, while POMC neurons are inhibited via α2A - adrenergic receptors. Thus, the coordinated differential modulation of the key hypothalamic neurons in control of energy homeostasis assigns noradrenalin an important role to promote feeding.